Flexible stay bolt



Aug.7,'192 8. 1,680,229

W. POLLOCK FLEXIBLE STAY BOLT Filed Sept. 8, 1926 2 Sheets-Sheet l I Wz 'fiiam Pa er/1 In 2 I 35% I attomwq Aug. 7, 1928.

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l atented 7, 1928.

WILLIAM POLLOCK, OF PITTSBURGH, PENNSYLVANIA.

FLEXIBLE STAY BOLT.

Application filed September 8, 1926. Serial No. 134,256

This invention relates to stay bolts such as are used in locomotive and other boilers to hold the fire box in proper spaced relation within the boiler shell;

It has long been recognized that the connection between the fire box of a boiler, especially. in locomotive boilers, must be of flexible nature so as to permit a certain amount of movement of the'fire box sheets relative to the wrapper sheet or wagon top while yet restraining this relative movement within due bounds; Practically all modern locomotive boilers are thus constructed and the flexibility is sought to be obtained by,

.. so-callcd, flexible stay bolts.

As examples of such flexible stay bolts attention is first called to the type shown in the patent to Dodds, No. 1,393,351, of October 11, 1921. In this type one end of the bolt is screwed into the fire box sheet and the other end connected to the wrapper sheet by a ball and socket. joint. This type is not truly flexible since the rigid connection requires bend of the bolt itself to permit unequal expansion or stretching of the sheets. A second type is that shown 1n the patent to Flannery, No. 1,359,587, of November 23,

1920, in which both ends of a bolt are supported after the manner of a ball and socket joint and the bolt is thus truly flexible.

However, the socket. at the wrapper sheet end is formed directly in that sheet and cannot be kept tight so that it is necessary to weld a cap over that end to keep the boiler from leaking at each stay bolt. Consequently the usual tell tale holes to indicate a broken bolt cannot be used. A third type which also flexible is shown in the patent to Pitkin, No. 1,480,321, of September 26, 1922,

. but in this type the straight thread at the fire box end prevents water and steam tightassured at that end while the taand thread at the wrapper sheet pered p 3 end renders difiicult the fitting of the parts at that end.

The principal. objects of the present invention are to provide an improved form of flexible stay bolt wherein the objections to former types of bolts such as noted above will be eliminated and wherein the construction is such that perfectly tight joints are formed both at the fire box and the wrapper sheet without preventing the use of tell tale holes.

With the above and other objects in view as will be hereinafter apparent, the invention consists in general of certain novel details of construction and combinations of parts hereina'iter fully described, illustrated in the accompanying drawings and specifically clalmed. i

In the accompanying drawings like characters of reference indicate like parts in the several views, and:

Figure 1 isa sect-ion through portions of the fire box and wrapper sheets or" a boiler showing the first step in the application of my stay bolt.

F igure 2 is a similar view to a somewhat smaller scale showing the second step in such application.

Figure 3 is a view with the bolt partly 111 section and showing the parts fully assembled and ready for finishing.

Figure 4 is a view similar to Figure 3 showing the finished bolt.

As here shown there is indicated a portion F of a fire box sheet and a portion S of a boiler shell or wrapper sheet.

The stay bolt itseli consists of three parts; namely, a fire box section, an intermediate section and a boiler shell section. The fire box section consists of a body having one end of general cylindrical form and threaded as at 10, an intermediate tapered and threaded part 11 formed with the smaller end of the tapered portion adjacent the straight threaded part 10, and having the remaining,end'squared as at 12 to receive a rotating device such as a wrench or .the socket of an electric or air bolt screwing machine.

The intermediate section 13 has at one end a threaded socket 14 to receive the threaded end and, at its other end, is provided with a somewhat elongated ball socket 15.

The remaining portion oil the bolt has a ball end .16 fitting in the socket 15 to rotate freelyand swing universally within limits. The body 17 of this part is of general cylindrical form and is threaded to fit in the cylindrical and threaded opening 18 of a tapered plug 19 having its smaller end toward the head 16. The remaining end 20 of this section of the bolt is squared to re ceive the squared socket 21 of a wrench 22 forming part of the means by which the bolt is applied. A sleeve 23 having a threaded portion 24 and a wrench receiving head 25 forms the remainder of the bolt applying means.

i the wrench 22 may be again In using the device the sheet F is drilled and taper tapped to receive, the tapered part 11. Similarly the sheet S is drilled and reamed as at 26 to receive the plug 19. The fire box section of the bolt is now. screwed'in place from inside the tire box, either manually or by machine, as shown in Figure 1. Next, the sleeve 23 is slipped over the shell end of the bolt until the square 20, which is made sufiioiently long for the purpose, can be engaged by the socket 21 after which the sleeve and the wrench, are relatively rotated so that the sleeve is forced tightly against the intermediate member as shown in Figure 2. The intermediate member, carried by the sleeve is now inserted through the opening 26 and theintermediate member is screwed tightly on the part 11. After this the sleeve is unscrewed by the aid of the wrench 22, which is used to prevent rotation of the shell end of the bolt, and the plug screwed on this shell end until it fits water and steam tight in theopening 26, the plug being preterably welded asat 27 as a matter 01' pre-' caution.

After as many of the bolts have been appliedas desired'and thus drawn-up tightly applied and rotated to unscrew each part 17 from its plug to whatever extent may be desired to allow proper play as, for instance, one half turn. Finally, the projecting ends are cut off and riveted as shown 'in Figure l, the plug 19 being recessed at 28 for this purpose It will be noted that'the connection with each sheet is tapered so that it is substantially impossible for a bolt to pull out of either sheet and this is an especially valuable point atthe fire box end where the rivetingsometimes burns oil or loosens. Also it will be noted that this construction does notin any way interfere with the tell tale holes '29.

' Having thus described the invention, What i socket in the remaining end; a second end section having a straight threaded body, a ball end held in said ballsocket and a remaining. end vportionadapted to receive a -renoh; and a tapered plug screwed on the last mentioned straight threaded portion, the smaller ends of the tapered threadedportion and of the plug confronting each other.

2. A boiler stay. boltcomprising-an end section having 'a central tapered and threaded portion, a straight threaded end portion and a wrench receiving opposite end portion, an intermediate section having a threaded socket in one vend receiving the threaded end portion and having a ball socket in the remaining end; a second end section having astraight threaded body, a ball end hold in said ball socket anda reanaining end portion adapted to receive a wrenchyand a tapered plug screwed on the last mentioned straight threaded portion, the smaller ends of the tapered threaded portion and of the plug confronting each other, said end sections having telltale holes eX- tending from their remote ends towards their" adjacent ends andv terminating in spaced relation to said adjacent ends.

in testimony whereof I affix my signature.

WILLIAM POLLOC'K. 

